1. Field of the Invention
This invention relates to a push on closure for a container and more particularly to a neck configuration for a container formed by blow molding technique for cooperating with a multiple-threaded closure by longitudinal movement of the closure with respect to the axis of the neck of the container.
2. Description of the Prior Art
Both plastic and metal closures for various bottles and containers which include a tamper-evident feature have been known for many years. In most cases, this tamper-evident feature comprises a lower shoulder or skirt portion of the closure which is in some way intended to fracture or break upon removal of the closure from the container, so that it then becomes evident that the container has been opened. While a large number of these closures have been known in the past, on a commercial basis, and particularly in connection with soda bottles and other such containers maintained under significant pressures, up until quite recently metal closures have predominated. These include closures such as shown in U.S. Pat. No. 3,812,991 which issued on May 28, 1974 to the Coca Cola Company, and many others.
In U.S. Pat. No. 4,625,875 to Carr, et al. there is disclosed a tamper-evident closure including a depending tamper-evident skirt member capable of being positioned by longitudinal force (i.e. pushed on) onto a neck of a container including a skirt collar wherein the closure is formed with an internal thread and the neck of the container is formed with a corresponding external thread and wherein the tamper-evident depends by angularly-formed arm members from the closure, and wherein the threads are of like multiple courses and wherein a groove of the skirt member of the closure engages the skirt collar of the container in an assembled relationship of the closure to the container.
The materials of the construction for the closure and container are of like flexible thermoplastic composition, e.g. polyethylene for the packaging of milk and like products. Extrusion blow molding of containers from a continuous tube of polyethylene is generally the process of choice.
There is the desire to use blow molding techniques, and other thermoplastic materials in forming containers, such as polyethylene terephthalate (PET), starting with the formation of a preform from which the container is subsequently formed in blow molds using the neck of the container as the transporting medium. While a neck finish of a predetermined diameter of a HDPE bottle may cooperate with a closure having a cooperating threaded configuration, however, a neck finish of a blow molded PET container would be thick, requiring excessive cycling times and potentially resulting in molding imperfections which would impair or inhibit cooperation with a push-on, multiple-threaded closure.